Mars - missions of the past and future

It is 10 years since the Mars Sojourner rover landed and the Mars Global Surveyor satellite began studying the red planet from orbit. So what do we know about Mars, and how is Australia involved in the latest missions designed to have people on the planet for the first time? Jonathan Nally reports.

Transcript

Robyn Williams: Today we go to Mars with Jonathan Nally.

Excerpt from Mars and its Canals: The possibility of life on a planet is merely a question of the planet's size, and then pursuantly that the character of that life is a matter of the planet's age. Mars is large enough to have begotten vegetation and small enough to be already old. All that we know of the physical state of the planet points to the possibility of both vegetal and animal life existing there. That Mars is inhabited by beings of some sort or other, we may consider as certain as it is uncertain what those beings may be.

Jonathan Nally: The words of Percival Lowell from his 1906 book Mars and its Canals. Lowell was an American astronomer who thought he saw signs of life on the red planet, seasonal vegetation patterns and a planet-wide canal system, obviously signs of an advanced civilisation, and all of it, as it turned out, a figment of his imagination.

It was the space missions of the 1960s and 70s that showed us once and for all that Mars was actually a cold, dead world, hardly the sort of place you'd find even the simplest forms of life, let alone a civilization that could build enormous engineering works. So space agencies began to lose interest. But that interest was piqued again in the 1990s. It's now ten years since the latest campaign of Mars space missions began. In July 1997, the Sojourner Rover was landed, and the Mars Global Surveyor satellite began its decade-long study of the planet from orbit. There have been other robotic missions since then of course, and plenty more to follow.

So why the renewed interest in Mars? On this tenth anniversary of the first Rover to land on another planet, we thought we'd take a look at the state of our knowledge of Mars and where we're heading with it.

Malcolm Walter is a geologist at Macquarie University and he's been doing Mars-related studies for many years.

Malcolm Walter: What we learnt gradually over the course of those missions (and there's have been quite a lot of missions to Mars or attempted ones anyway) was that at least early in its history it was warmer and wetter, much wetter than it is now. We know that because we'd see dry river valleys and dry lake beds, maybe even a former ocean in the northern half of the planet. So that opened up the possibility that there might have been life on Mars.

Jonathan Nally: Because if you'd had water, there could have been life, as we know it at least.

Malcolm Walter: Yes, all life we know of on Earth requires liquid water, so that was the starting point. It was a fascination even before then anyway just with the geology of Mars and understanding another planet. So we could compare that planet with the Earth and learn a lot about the Earth.

Jonathan Nally: Because we do see some evidence of water or have seen for quite a long time, and they are these polar icecaps...they're part water ice and part carbon dioxide. Is that correct?

Malcolm Walter: Yes, that's correct.

Jonathan Nally: Where has the water gone then? We do see these huge floodplains and river valleys and things that have obviously been carved by some sort of liquid...at least that has been the assumption, and it's pretty certain now. So where do they think the water has gone?

Malcolm Walter: A lot of us consider it to be underground, it has just soaked into what we call the regolith, the fractured rocks on the surface of the planet, and some has been lost in space, probably quite a bit has been lost in space.

Jonathan Nally: How do you lose water into space?

Malcolm Walter: You break down the H 2O into H 2 and O, and the H 2 escapes because there's not enough gravity to hold it to the planet.

Jonathan Nally: One of the differences in Mars is that it is unprotected from the solar radiation, and anything on the surface is going to get zapped basically by the ultraviolet.

Malcolm Walter: Yes, that's right, but it doesn't take much sand or whatever, silt, to provide protection, so you can imagine habitats within a few millimetres in fact of the surface.

Jonathan Nally: Back in the 70s, about 30 years ago in fact, NASA landed two landers on Mars, the Vikings-Viking I and Viking II-and they had some experiments on board to directly test for signs of life, which hasn't been done since. These directly tried to test to see if there was any microbial life there, and they got some conflicting results, didn't they.

Malcolm Walter: Yes, there were several different experiments running on the two Vikings and one experiment in particular showed signs that at first were interpreted as indicating life, but other explanations were found later. So those experiments were inconclusive really. And in fact if you did the same things in the Atacama Desert in some places, in the driest part of the Atacama you wouldn't find any evidence for life there either.

Jonathan Nally: Is that right? Even though there obviously is life there in the Atacama somewhere?

Malcolm Walter: There is but it's extremely sparse and hard to find. There's plenty of life elsewhere on Earth but if you choose to land in a place like the Atacama Desert, which is equivalent to where the Vikings landed really in some ways...

Jonathan Nally: The Atacama Desert of course is in the high plateau in Chile in South America, and there are other places around the world that are like that, that are dry and largely waterless. Places in Australia perhaps?

Malcolm Walter: Not as dry as the Atacama. The other really severe desert is the Namib in Namibia, Southern Africa. In Australia the deserts were drier in the past, but if you go out to any of the deserts now there is scrubby vegetation, a bit of grass.

Jonathan Nally: So Vikings would find life in the Australian desert?

Malcolm Walter: They would have.

Jonathan Nally: And so why haven't those tests been repeated? Why haven't they sent better tests back to Mars do you think?

Malcolm Walter: It went out of fashion. When the Vikings failed to find convincing evidence of life, the search switched to looking for evidence of past life rather than extant or living life. So subsequent missions focused on looking for water; the mantra is to follow the water and you might find evidence of life or past life. There's been no attempt to do direct life-detection experiments since then but there will be in the near future.

Jonathan Nally: So, after Viking the assumption was Mars is dead, we're pretty confident there's nothing there now, so let's just look at the geological past of the planet and see what might have been there in the past. So now it's a bit different. You just mentioned that perhaps we'll go back and look for directly signs of life. So what has changed in those 30 years? Why now do we think that the likelihood is better?

Malcolm Walter: We're learned a huge amount in the last 10 or 15 years, and one thing that we're learned just in the last five years is that there's something still forming little gullies that look like water-formed gullies on the escarpments and the sides of craters and so on. Something is still flowing, at least intermittently, on the surface of Mars. That opens up the possibility that there could still be life very close to the surface. The mechanism of the formation of those gullies isn't really understood but certainly it's a reasonable working hypothesis that from time to time liquid water comes to the surface, and maybe bringing a subterranean microflora with it to the surface.

Jonathan Nally: So there actually could be reservoirs of liquid water there under the surface?

Malcolm Walter: There are almost certain to be. All the geological models of Mars indicate that the interior of the planet is warm, just as the interior of the Earth is very hot, Mars is at least warm, and that therefore there would be liquid water.

Jonathan Nally: I've heard a suggestion that here on Earth, if you added up the mass of life that's underground, all the microbes and little things that live under the surface, that that actually might add up to more mass than lives on the surface of this planet. Is that a bit fanciful? And whether it is or not, is that the sort of thing they're thinking about on Mars; there could be a large population of these things living underground?

Malcolm Walter: No, it's not fanciful. We don't really know how much life there is underground. We do know there is plenty of life, microbial life we're talking about. It could have a mass greater than the mass of physical life on the surface of the Earth but it's just not known yet, and that is what we're thinking about for the sub-surface of Mars, that there could be a similar deep hot biosphere, as it's called here.

Jonathan Nally: So there could be lots of life on Mars just waiting to be found. Lowell had something to say about that.

Excerpt from Mars and its Canals: Rationally viewed, the general problem of life on other worlds reduces itself to a question of conditions. The possibility of life becomes one of habitat. If the environment be suitable, life will ensue.

Jonathan Nally: A couple of months ago on The Science Show we heard from Darlene Lim. She's a NASA geo-biologist who's involved with testing potential Mars technologies in remote corners of the Earth. But it's not widely known that some Australian researchers are intricately involved in these efforts too. A group called the Mars Society Australia is quietly beavering away on technologies that might be used for the first manned Mars missions. Dr Graham Mann from Murdoch University in Western Australia is one of those researchers and he's working on a deluxe version of the Apollo Moon Buggy.

Graham Mann: What it is is a prototype of a vehicle which would be used on Mars to carry explorers away from the main landed spacecraft and be able to explore a larger area. Even on the Moon, in project Apollo, it became a big limiting factor about exploration, that you could only walk out a certain distance away from the spacecraft and then have to walk back. And so even there they started to use small golfcart-like vehicles, Luna Rover, as they were called, even though it was not a robot but a moving vehicle. NASA calls anything with wheels on another planet a Rover.

So now a Mars Rover would be a pressurised vehicle, something like a large camper wagon, but it has to be really more like a land-going space craft. It would have to have all the life support systems, navigation systems, an airlock, everything required to support human life away from the main land at base.

Jonathan Nally: So what are the conditions like on Mars? How different is it to here on Earth, and what sort of things do you need to protect yourself against on that planet?

Graham Mann: In some ways Mars is the most Earth-like planet of all; it has a nice solid surface, and the temperature conditions, though rather cold, are in some ways something like the conditions on Earth in the polar regions or perhaps in the middle of winter. It's very dry, very dusty, very red and devoid of vegetation of course, at least as far as we know. We believe that the very low pressure (the pressure is only very few millibars and therefore something like being at the top of the highest mountain on Earth) is something that you would need to do, you would have to take your own oxygen wherever you go, and also you'll need to be protected against the very low pressure conditions, as if you were in space almost. And there are probably very high levels of radiation on the surface as well since the atmosphere won't protect one as much as it would on Earth.

Jonathan Nally: So there's really quite a level of different things you need to guard yourself against on Mars. This vehicle that you're designing, how many people could fit inside it, and how long is it designed to last? How long will they last inside before they have to get back to base?

Graham Mann: We're designing the vehicle to be able to carry four persons away from the base for at least two weeks at a time.

Jonathan Nally: Two weeks at a time? That's a lot of supplies you have to carry.

Graham Mann: That's so, but the reason for that is we want to expand the range of exploration as much as possible. Every extra kilometre you can travel away greatly expands...you know, the area of a circle expands relative to the radius, and so it makes a big difference how far you can go, and that is the amount of area that you can explore.

Jonathan Nally: You'd need to carry a lot of supplies then for four people for two weeks.

Graham Mann: Yes, and that's a problem. You need to carry oxygen, water, food and just everything that you need. You're a very long way from home and you have to have spares in case something breaks down and a very good deal of equipment. So this is a very challenging design problem, and that's one of the reasons why we think it's not too soon to begin now building prototype vehicles, an actual vehicle which we can start experimenting with in the deserts of Australia (a very Mars-like place by the way, in some places) and then we will learn what's required for that. It's our goal in the Australian Mars Society to put the results of those experiments (and we've been doing them for quite a few years now) into the hands of the actual contractors who would build the flight hardware eventually.

Jonathan Nally: So what stage are you at? Have you built one of these machines? Have you tested it in the desert?

Graham Mann: I have tested vehicles that have been developed in the United States, the earlier test prototypes, and at the Mars Desert Research Station in Utah, very salty, desert-like conditions in Utah. I tested some of these vehicles. They were early prototypes just based around trucks. This vehicle that we're building in Australia, called the Starchaser Marsupial Rover, that is the first vehicle really that's been custom built from the ground to be a Mars prototype, and it's under construction now but not fully completed.

Jonathan Nally: So when do you think you'll have that done and be able to roll it out into the deserts of Western Australia?

Graham Mann: We hope to have it done by the end of the year but progress has been a little slow on it. It's quite complicated to do, especially on a low budget, but we do have sponsorship from a UK aerospace firm and one or two other companies here in Australia.

Jonathan Nally: This prototype, will it be a fully functioning prototype such that the people inside are totally enclosed and have to live off the systems on board, or will they get their breathing oxygen and everything from the outside world?

Graham Mann: This is what we call a medium fidelity prototype, which means that some parts of the vehicle as it would be on Mars were modelled but other parts were not. So it's using a conventional diesel engine to drive it, for example. The persons inside are breathing air but they're still having to be enclosed in the same sorts of ways, they have to move through an airlock and put on a spacesuit before they're allowed to leave the vehicle, and many of the technologies that would be used in the real thing are modelled there.

Jonathan Nally: So it has an airlock so the people can get outside. Once you get outside, what do you then have to do to protect yourself against the Martian environment? Do you have to wear one of these big, bulky, Apollo-style spacesuits that the astronauts used back in the 1960s and 70s?

Graham Mann: When most people think of exploring another world they have a vision of the Apollo astronauts and their Apollo era spacesuits, but of course those were designed back in the early 60s and technology has moved along a good deal since then. Still, the Mars Society Australia is making a contribution here as well. We think that a completely different concept in how spacesuits could be designed to protect you against low pressure and the low temperatures that you'd be experiencing there is called for. This is Project Mars Skin, and what that is is something called a mechanical counterpressure suit, and instead of surrounding the astronaut in an envelope of gas that's pumped up like a balloon, it would be a form-fitting garment that stretches over the astronaut's skin and presses back against the skin to avoid the excesses of low pressure.

We believe that a suit constructed in this way could have a number of great advantages, not least of which is it couldn't easily be punctured and leak. And also it would help the astronauts ergonomically; that is, they're not having to work so hard against pulling the...most people don't know, but when you're in one of those Apollo Moon suits you're really working very hard just to move your limbs, so the mechanical counterpressure suit could very much reduce the workload of simply moving inside one.

Jonathan Nally: I've got this picture in my mind of someone wearing something a bit like a wetsuit combined with one of those G-suits that a fighter pilot might use in an aircraft when pulling high turns and things. Is it a bit like that?

Graham Mann: That's what our prototypes look like, yes. Of course you still need a gas envelope over your head because you need to breathe, and there's good reasons to think that maybe the central part of your body would also need those things, but we're experimenting with that presently and we have a third generation of Mars Skin suit having been tested at the Utah station and also out in the desert of central Australia, a place called Arkaroola where we have a test site.

Jonathan Nally: Really? So you have actually been testing these. Is it very difficult to test that on an Earthly environment? Do you have to make some adaptations because of the greater temperatures here and the greater air pressure?

Graham Mann: Certainly. Again, there are only certain things we can test in the desert environment. What we use that for is to try out the durability, the range of motion that the astronaut would have, and some other factors about being out in the field with a device like that. For pressure testing, of course, we need to go into hyperbaric chambers which would test those sorts of conditions.

Jonathan Nally: And so is this being done by the Mars Society Australia under your own aegis or is this NASA backed? Is NASA interested in this sort of work?

Graham Mann: Certainly NASA is very interested. In fact, the Mars Society originally grew out of NASA. There was something called the Mars Underground, which was very dissatisfied back in the 90s with the lack of progress towards a human Mars mission, so this worldwide body of interested people got up, almost as a protest against NASA's lack of progress in exploration. Now of course there are real NASA projects aimed towards getting to Mars, but the Mars Society still believes that those are too slow. But they do have projects which will help support this, and some of the money for the Mars Society does come now from NASA, for the first time in ages.

Jonathan Nally: So the first astronauts on Mars could be wearing an Australian-designed spacesuit?

Graham Mann: That's certainly possible. We're not sure how much of the technology would come from our developments but we're hoping to make a contribution there.

Jonathan Nally: Of course it's all very well having a groovy Rover to drive around in and a skin-tight spacesuit to protect you, but where would you live? You'd need a habitat of some kind. Traditional ideas call for sending living modules that use heat shields and parachutes to survive entry into the Martian atmosphere, landing on legs like the Apollo lunar landers. But that's not the only way to do it.

Graham Mann: The Australian Mars Society has an alternative approach to this. We believe that allowing the habitat to drop on a parachute would make it very difficult to cause the vehicle to arrive at a specific destination. We have a plan for an alternative type of station which could be flown down to the surface and landed horizontally. It's a long cylinder with a kicked-up snout, makes it look rather like a guineapig, and we call this a horizontally bent biconic structure. It is around this that our design for a Mars habitat...which we hope to deploy in the South Australian desert in the future.

Jonathan Nally: So this guineapig-shaped tube would fly all the way to Mars and then somehow have to enter the atmosphere and fly all the way down to the ground. So it would need a big heat shield, would it?

Graham Mann: The vehicle itself would be designed so that as it entered the atmosphere, the shape of the object itself would act as the heat shield, and it would glide down to the surface and land on jets gently on the ground.

Jonathan Nally: And how big would this be?

Graham Mann: This is about 25 metres long and about five metres in diameter.

Jonathan Nally: That's pretty big.

Graham Mann: Quite a large structure, yes. It has to carry perhaps as many as six persons for quite a long period of time, and of course we would want to leave it on the surface so that future astronauts could also use it.

Jonathan Nally: And would you be able to live off the land once you got there? Would that be a requirement for a long duration Mars mission that you might not be able to or want to take all the supplies with you? What can you get in situ on the planet?

Graham Mann: Yes, most modern conceptions of a Mars mission would involve travelling light and living off the land. The technical term for that is, as you say, in situ resource utilisation. That means finding things that you need on the surface of Mars. It's not like the Moon, you can extract minerals from the ground, you can extract oxygen from the air. Most conceptions of the modern Mars mission have exactly that; you would land something there, perhaps as much as a year ahead of the landed mission, a machine which would have fuel tanks on it which you could use to collect, let's say, a gas like methane for rocket propulsion, and liquid oxygen would be tanked up for breathing and for other purposes. So that's one way that you could live off the land on Mars.

Jonathan Nally: But all this sounds very expensive, and even a little far-fetched. In a time of constrained budgets and huge challenges facing us here on this planet, isn't sending people to Mars an extravagance that we can do without?

Graham Mann: The really important thing about going to Mars is that it's a massive challenge to humanity. At a time when there's nothing but bad news in the newspapers, think what a landing on Mars would mean to a lot of young people. It would be such an inspiration. I'm old enough to remember the Apollo days and how people thought we can do anything now, humanity on the move, you know? That was a really important thing for me when I was a child and I'd like my students and younger people today to experience that again.

Jonathan Nally: It would have to be an international venture I assume because it's such a huge undertaking.

Graham Mann: I think so. At the moment we have three projects that are associated with this. There's the United States' project Constellation, a rather slow boat via the Moon...that's not planning to land until 2030, that's way too slow for any of the Mars Society, we want it done ten years earlier than that. There's the Russians...the Russians are extremely interested in getting to Mars and they wouldn't mind beating the Americans there, you bet. I know this for a fact because I talk to a lot of people from the Russian space agency, and they are very, very keen to get there first, and they're running this year a 500-day simulation of Mars at the Moscow Institute of Biomedical Problems. Then there's the European project Aurora which is also a plan to send human beings to Mars. So that's three projects right there, and we may very well end up, when we get a bit closer to the dates when these projects will mature, with another kind of space race, but hopefully this time a less militaristic and a more productive one.

When people ask me about going to Mars I say, think of Australia 250 years ago, it was exactly like this; a long six-month trip, a hazardous voyage, maybe you wouldn't survive it, perhaps when you got there...what would be there? There's nothing there and why would you want to go? And look at us now. Can anything that those people back in Europe did compare in importance to the fact that some of them were willing to go out and have a look at Australia and see what potential it had? I think in future there will be a human colony on Mars, I hope in future there will be a colony on Mars, and I think they'll look back to Earth and they'll perhaps maybe once in a while remember that there were people who thought about it and wanted to do it when it didn't seem like a good idea. And that's us.

Jonathan Nally: So if we want to find signs of life on Mars, maybe all we have to do is wait a couple of decades and that life might be Homo sapiens, and then maybe Percival Lowell's words, which in retrospect seem so fanciful now, might one day turn out to be true after all.

Excerpt from Mars and its Canals: Someday our own geology, meteorology and the rest will stand indebted to study of the planet Mars for advance along their respective lines. In a not distant future we shall be repaid with interest, and what that other world shall have taught us will redound to a better knowledge of our own and of that cosmos of which the two form part.

Robyn Williams: That report on Mars then and now was by Jonathan Nally, our resident Martian enthusiast.

Guests

Malcolm Walter

Director Australian Centre for Astrobiology Macquarie University NSW Australia